net: hns: fix for promisc mode in HNS driver

If set promisc mode when there is some traffic, The service nic will
cause system halted. We reserve the last 6 tcam entry for the 6 ports.
If promisc mode is enabled, we can config the relative tcam as fuzzy
matching and set to be valid, or set the tcam to be invalid

Signed-off-by: Kejian Yan <yankejian@huawei.com>
Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>